scholarly journals Does plant architectural complexity increase with increasing habitat complexity? A test with a pioneer shrub in the Brazilian Cerrado

2013 ◽  
Vol 73 (2) ◽  
pp. 271-277 ◽  
Author(s):  
FAO Silveira ◽  
EG Oliveira
Keyword(s):  
Soil Fertility ◽  
Habitat Complexity ◽  
Plant Traits ◽  
Canopy Cover ◽  
Southeastern Brazil ◽  
Ecological Gradients ◽  
Higher Plant ◽  
Fertility Gradient ◽  
Heterogeneous Habitats ◽  
Neotropical Savannas

Understanding variation in plant traits in heterogeneous habitats is important to predict responses to changing environments, but trait-environment associations are poorly known along ecological gradients. We tested the hypothesis that plant architectural complexity increases with habitat complexity along a soil fertility gradient in a Cerrado (Neotropical savanna) area in southeastern Brazil. Plant architecture and productivity (estimated as the total number of healthy infructescences) of Miconia albicans (SW.) Triana were examined in three types of vegetation which together form a natural gradient of increasing soil fertility, tree density and canopy cover: grasslands (campo sujo, CS), shrublands (cerrado sensu strico, CE) and woodlands (cerradão, CD). As expected, plants growing at the CS were shorter and had a lower branching pattern, whereas plants at the CD were the tallest. Unexpectedly, however, CD plants did not show higher architectural complexity compared to CE plants. Higher architectural similarity between CE and CD plants compared to similarity between CS and CE plants suggests reduced expression of functional architectural traits under shade. Plants growing at the CE produced more quaternary shoots, leading to a larger number of infructescences. This higher plant productivity in CE indicates that trait variation in ecological gradients is more complex than previously thought. Nematode-induced galls accounted for fruit destruction in 76.5% infructescences across physiognomies, but percentage of attack was poorly related to architectural variables. Our data suggest shade-induced limitation in M. albicans architecture, and point to complex phenotypic variation in heterogeneous habitats in Neotropical savannas.

Abiotic factors modulate phenotypic plasticity in an apomictic shrub [Miconia albicans (SW.) Triana] along a soil fertility gradient in a Neotropical savanna

2011 ◽  
Vol 59 (3) ◽  
pp. 274 ◽  
Author(s):  
Cibele S. Bedetti ◽  
Débora B. Aguiar ◽  
Maria C. Jannuzzi ◽  
Maria Z. D. Moura ◽  
Fernando A. O. Silveira
Keyword(s):  
Phenotypic Plasticity ◽  
Soil Fertility ◽  
Leaf Area ◽  
Plant Traits ◽  
Abiotic Factors ◽  
Leaf Traits ◽  
High Plasticity ◽  
Fertility Gradient ◽  
Heterogeneous Habitats ◽  
Soil Fertility Gradient

Phenotypic plasticity is an important means by which plants cope with environmental heterogeneity; therefore, understanding variation in plant traits in heterogeneous habitats is important to predict responses to changing environments. In this study, we examined the patterns of intraspecific variation in leaf traits of Miconia albicans (Melastomataceae), a widespread, obligatory apomictic shrub, across a soil fertility gradient in the Cerrado (Brazilian savanna). We predicted high plasticity because selection favours high phenotypic plasticity in asexual populations with low genetic variability. Leaves were sampled in campo sujo (grassland), cerrado (savanna) and cerradão (woodland) in south-eastern Brazil during both dry and rainy seasons to calculate leaf area, specific leaf area, leaf tissue thickness, trichome and stomata density. We found significant between-season variation in leaf traits, indicating that the production of season-specific leaves is a strategy to cope with the strong seasonality. Both multivariate analysis and the relative distance plasticity index indicate lower plasticity during the dry season, especially under shade. Our results show that the phenotypic plasticity can be modulated by changes in abiotic factors and the combination of shade and drought can limit the expression of phenotypic plasticity.

scholarly journals A semi-quantitative approach for modelling crop response to soil fertility: evaluation of the AquaCrop procedure

2014 ◽  
Vol 153 (7) ◽  
pp. 1218-1233 ◽  
Author(s):  
H. VAN GAELEN ◽  
A. TSEGAY ◽  
N. DELBECQUE ◽  
N. SHRESTHA ◽  
M. GARCIA ◽  
...  
Keyword(s):  
Soil Fertility ◽  
Grain Yield ◽  
Soil Water ◽  
Crop Production ◽  
Water Productivity ◽  
Canopy Cover ◽  
Quantitative Approach ◽  
Fertility Level ◽  
Crop Response ◽  
Aquacrop Model

SUMMARYMost crop models make use of a nutrient-balance approach for modelling crop response to soil fertility. To counter the vast input data requirements that are typical of these models, the crop water productivity model AquaCrop adopts a semi-quantitative approach. Instead of providing nutrient levels, users of the model provide the soil fertility level as a model input. This level is expressed in terms of the expected impact on crop biomass production, which can be observed in the field or obtained from statistics of agricultural production. The present study is the first to describe extensively, and to calibrate and evaluate, the semi-quantitative approach of the AquaCrop model, which simulates the effect of soil fertility stress on crop production as a combination of slower canopy expansion, reduced maximum canopy cover, early decline in canopy cover and lower biomass water productivity. AquaCrop's fertility response algorithms are evaluated here against field experiments with tef (Eragrostis tef (Zucc.) Trotter) in Ethiopia, with maize (Zea mays L.) and wheat (Triticum aestivum L.) in Nepal, and with quinoa (Chenopodium quinoa Willd.) in Bolivia. It is demonstrated that AquaCrop is able to simulate the soil water content in the root zone, and the crop's canopy development, dry above-ground biomass development, final biomass and grain yield, under different soil fertility levels, for all four crops. Under combined soil water stress and soil fertility stress, the model predicts final grain yield with a relative root-mean-square error of only 11–13% for maize, wheat and quinoa, and 34% for tef. The present study shows that the semi-quantitative soil fertility approach of the AquaCrop model performs well and that the model can be applied, after case-specific calibration, to the simulation of crop production under different levels of soil fertility stress for various environmental conditions, without requiring detailed field observations on soil nutrient content.

scholarly journals Can we predict dispersal guilds based on the leaf-height-seed scheme in a disjunct cerrado woodland?

2008 ◽  
Vol 68 (3) ◽  
pp. 553-559 ◽  
Author(s):  
AVF. Jardim ◽  
MA. Batalha
Keyword(s):  
Leaf Area ◽  
Specific Leaf Area ◽  
Field Experiments ◽  
Plant Traits ◽  
Seed Mass ◽  
Soil Nutrient ◽  
Canopy Height ◽  
Southeastern Brazil ◽  
Plant Canopy ◽  
Frugivorous Birds

Although there have been advances in methods for extracting information about dispersal processes, it is still very difficult to measure them. Predicting dispersal groups using single readily-measured traits would facilitate the emergence of instructive comparisons among ecological strategies of plants and offer a path towards improved synthesis across field experiments. The leaf-height-seed scheme consists of three functional traits: specific leaf area, plant canopy height, and seed mass. We tested, applying logistic regression analysis, whether these traits are potential predictors of dispersal guilds in a disjoint cerrado woodland site in southeastern Brazil. According to our results, none of the plant traits studied could predict dispersal guild; this means that abiotically and biotically dispersed species showed similar values of specific leaf area, height, and seed mass. The species of both guilds exhibited sclerophylly, probably a result of the typical soil nutrient deficiency of cerrado, which also may have placed constraints upon plant canopy height regardless of the dispersal mode. In the cerrado, some abiotically dispersed trees might present higher than expected seed mass as support to the investment in high root-to-shoot ratio at the seedling stage. Seeds of bird-dispersed species are limited in size and mass because of the small size of most frugivorous birds. Since soil nutrient quality might contribute to the similarity between the dispersal guilds regarding the three traits of the scheme, other plant traits (e.g., root depth distribution and nutrient uptake strategy) that detail the former should be considered in future predictive studies.

scholarly journals Phylogenetic overdispersion of plant species in southern Brazilian savannas

2009 ◽  
Vol 69 (3) ◽  
pp. 843-849 ◽  
Author(s):  
IA. Silva ◽  
MA. Batalha
Keyword(s):  
Phylogenetic Relationships ◽  
Plant Traits ◽  
Environmental Filtering ◽  
Southeastern Brazil ◽  
Ecological Communities ◽  
Ecological Interactions ◽  
Ecological Processes ◽  
Phylogenetic Structure ◽  
History Of ◽  
Phylogenetic Overdispersion

Ecological communities are the result of not only present ecological processes, such as competition among species and environmental filtering, but also past and continuing evolutionary processes. Based on these assumptions, we may infer mechanisms of contemporary coexistence from the phylogenetic relationships of the species in a community. We studied the phylogenetic structure of plant communities in four cerrado sites, in southeastern Brazil. We calculated two raw phylogenetic distances among the species sampled. We estimated the phylogenetic structure by comparing the observed phylogenetic distances to the distribution of phylogenetic distances in null communities. We obtained null communities by randomizing the phylogenetic relationships of the regional pool of species. We found a phylogenetic overdispersion of the cerrado species. Phylogenetic overdispersion has several explanations, depending on the phylogenetic history of traits and contemporary ecological interactions. However, based on coexistence models between grasses and trees, density-dependent ecological forces, and the evolutionary history of the cerrado flora, we argue that the phylogenetic overdispersion of cerrado species is predominantly due to competitive interactions, herbivores and pathogen attacks, and ecological speciation. Future studies will need to include information on the phylogenetic history of plant traits.

scholarly journals Effect of Farmyard Manure, Lime and Inorganic Fertilizer Applications on Soil pH, Nutrients Uptake, Growth and Nodulation of Soybean in Acid Soils of Western Kenya

2018 ◽  
Vol 10 (4) ◽  
pp. 199 ◽  
Author(s):  
Hillary M. O. Otieno ◽  
George N. Chemining’wa ◽  
Shamie Zingore
Keyword(s):  
Soil Fertility ◽  
Nutrient Uptake ◽  
Soil Ph ◽  
Block Design ◽  
Farmyard Manure ◽  
Control Treatment ◽  
Nodule Formation ◽  
Higher Plant ◽  
Inorganic Fertilizers ◽  
Western Kenya

Soybean is an important crop with nutrition, economic and soil fertility improvement benefits to farmers. However, its production in western Kenya is partly constrained by low soil pH and soil fertility levels. A greenhouse pot study was conducted to evaluate the effects of inorganic fertilizers, farmyard manure and lime application on soil pH, nutrient uptake, growth and nodulation of soybean grown in acidic soils from western Kenya. The experiment was set up in a randomized complete block design with eight treatments: control; NPK; manure; lime; manure+lime; NPK+manure; NPK+lime and manure+lime+NPK. Significant effects of inorganic fertilizers, manure and lime applications were observed on all the variables. Manure, lime and manure+lime treatments increased soil pH by 1.33, 2.19 and 2.28, respectively, above the control treatment. The shoot N was lower under control (1.71-1.81%), NPK (1.85-1.98%) and manure (2.00-2.11%) than under all other treatments. Treatments NPK+lime and manure+lime+NPK recorded higher uptake of P and K nutrients than all other treatments. The control and NPK treatments recorded shorter plants and low leaf area and above-ground biomass compared to other treatments. The NPK+lime and manure+lime+NPK treatments recorded higher plant height and aboveground biomass than other treatments. Lime+manure treatment recorded highest nodule numbers and dry weights per plant. Positive relationships were observed between pH and N, P and K nutrient uptake (R2 ranged between 0.30 and 0.77) and between biomass and N, P and K nutrient uptake (R2 ranged between 0.68 and 0.99). From this study, use of manure and lime could result in improved soil pH for better uptake of nutrients, nodule formation and productivity of soybean in Western Kenya.

scholarly journals Landscape effects on the occurrence of ichthyofauna in first-order streams of southeastern Brazil

2016 ◽  
Vol 28 (0) ◽  
Author(s):  
Gabriela Santos Tibúrcio ◽  
Carolina da Silva Carvalho ◽  
Fabio Cop Ferreira ◽  
Roberto Goitein ◽  
Milton Cezar Ribeiro
Keyword(s):  
Species Richness ◽  
Functional Groups ◽  
Riparian Vegetation ◽  
Riparian Forest ◽  
Vegetation Type ◽  
Canopy Cover ◽  
Southeastern Brazil ◽  
Temperature Conductivity ◽  
Explanatory Variables ◽  
First Order

Abstract Objective In this study we aimed to understand how extrinsic environmental factors measured in the watercourses and the surrounding landscape influence the ichthyofauna of first-order streams. Methods Data were collected within the Corumbataí River Basin, São Paulo, southeastern Brazil, during the dry season of 2012. We sampled the ichthyofauna in 13 stretches of streams distributed across four river sub-basins. The stretches differed in relation to the presence/absence of riparian forest, the predominant type of matrix and the percentage of forest. Response variables were species richness and the occurrence of functional groups and explanatory variables include both local and landscape structures from the surrounding environment. Local variables comprised the following water quality and structural attributes: pH, temperature, conductivity, turbidity, flow rate, depth, width, type of substrate. Landscape variables included presence/absence of riparian vegetation, type of vegetation, type of matrix, percentage of forest and canopy cover. Results A total of 268 individuals were recorded, which were distributed among 12 species. The landscape structure influenced the occurrence of functional groups in first-order streams, especially allochthonous-feeders, nektonic and hypoxia-intolerant species. The presence of riparian forest was the most important predictor. Species richness was negatively related to the presence of riparian vegetation, supporting the hypothesis that degraded landscapes lead to a reduction in diversity. Conclusion The protection of riparian vegetation is critical to the maintenance of ichthyofauna diversity in first-order streams. The presence or absence of riparian vegetation differently affected the occurrence of species depending on their functional characteristics, particularly those related to the tolerance to hypoxia, source of alimentary items and the position in the water column.

Nutrient fluxes in litterfall and decomposition in four forests along a gradient of soil fertility in southern Ohio

1984 ◽  
Vol 14 (6) ◽  
pp. 794-802 ◽  
Author(s):  
Ralph E. J. Boerner
Keyword(s):  
Soil Fertility ◽  
Nutrient Availability ◽  
Soil Nutrient ◽  
Nutrient Concentrations ◽  
Strongly Correlated ◽  
Nitrogen And Phosphorus ◽  
Soil Nutrient Availability ◽  
Nutrient Mineralization ◽  
Nutrient Levels ◽  
Fertility Gradient

To determine how soil nutrient availability influences nutrient cycling, fluxes of nutrients through litterfall and decomposition were determined for four forest stands similar in all respects except soil nutrient availability and microclimate, within Neotoma Valley, a small watershed in southern Ohio, U.S.A. Litterfall varied from 10 to 60% among sites while nutrient concentrations and masses in new leaf litter varied as a function of extractable soil nutrient levels. Mass loss from litterbags was significantly higher in more fertile sites. Stepwise regression indicated that initial litter nitrogen and phosphorus concentrations were strongly correlated with relative decomposition rate while lignin concentration and microclimate variables were only correlated weakly. Thus, both litterfall nutrient transfers and decomposition rates were under the control of soil nutrient levels. Nitrogen was immobilized in litter at all sites during the 1st year of decay; litter from more fertile sites mineralized nitrogen during the 2nd year, while that from less fertile sites continued to immobilize nitrogen. Phosphorus and calcium mineralization rates were strongly correlated with the availability of these elements in the soil. Magnesium and potassium were leached rapidly from litter; amounts mineralized were correlated with amounts in litterfall. Interrelations among soil fertility, litterfall, and nutrient mineralization, as well as litter redistribution, are discussed as processes important in the development and maintenance of the soil fertility gradient in this watershed.

Effect of initial soil fertility and integrated plant nutrition system (IPNS) on yield and NPK uptake by brinjal on an Alfisol

2015 ◽  
Author(s):  
V. Dhinesh ◽  
R. Santhi
Keyword(s):  
Soil Fertility ◽  
Plant Nutrition ◽  
Tamil Nadu ◽  
Second Phase ◽  
Fertilizer N ◽  
Available N ◽  
Fertility Gradient ◽  
Npk Uptake ◽  
Initial Soil ◽  
Four Levels

Following Inductive methodology (fertility gradient concept), a field experiment was conducted to study the effect of initial soil fertility and Integrated Plant Nutrition System (IPNS) on the yield of brinjal (var. CO 2) on Typic Rhodustalf of Tamil Nadu. In the first phase of the experiment, variations in soil fertility with reference to soil available N, P and K was established among the three fertility strips with the addition of fertilizers at graded levels and by growing fodder sorghum as gradient crop. In the second phase viz., the test crop experiment with brinjal, consisted of four levels each of fertilizer N, P2O5 and K2O and three levels of farm yard manure (FYM). The highest yield of 35.8 t ha-1was recorded with 150:75:75 kg ha-1 of fertilizer N, P2O5 and K2O along with 12.5 t ha-1 of FYM in strip III with initial soil available NPK status of 203, 34 and 500 kg ha-1 respectively. The fruit yield as well as NPK uptake by brinjal had increased with increase in initial soil fertility and with increase in the levels of fertilizer N, P2O5 and K2O and FYM.

Population dynamics of hispid cotton rats (Sigmodon hispidus) across a nitrogen-amended landscape

2003 ◽  
Vol 81 (6) ◽  
pp. 994-1003 ◽  
Author(s):  
Jay E Clark ◽  
Eric C Hellgren ◽  
Eric E Jorgensen ◽  
Susan J Tunnell ◽  
David M Engle ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Reproductive Success ◽  
Survival Rates ◽  
Canopy Cover ◽  
Sigmodon Hispidus ◽  
Old Field ◽  
Higher Plant ◽  
Population Growth Rates ◽  
Low Level ◽  
Cotton Rats

We conducted a mark–recapture experiment to examine the population dynamics of hispid cotton rats (Sigmodon hispidus) in response to low-level nitrogen amendments (16.4 kg nitrogen/ha per year) and exclosure fencing in an old-field grassland. The experimental design consisted of sixteen 0.16-ha plots with 4 replicates of each treatment combination. We predicted that densities, reproductive success, movement probabilities, and survival rates of cotton rats would be greater on nitrogen-amended plots because of greater aboveground biomass and canopy cover. Population densities of cotton rats tended to be highest on fenced nitrogen plots, but densities on unfenced nitrogen plots were similar to those on control and fenced plots. We observed no distinct patterns in survival rates, reproductive success, or movement probabilities with regard to nitrogen treatments. However, survival rates and reproductive success tended to be higher for cotton rats on fenced plots than for those on unfenced plots and this was likely attributable to decreased predation on fenced plots. As low-level nitrogen amendments continue to be applied, we predict that survival, reproduction, and population-growth rates of cotton rats on control plots, especially fenced plots with no nitrogen amendment, will eventually exceed those on nitrogen-amended plots as a result of higher plant-species diversity, greater food availability, and better quality cover.

Seed availability constrains plant species sorting along a soil fertility gradient

2010 ◽  
pp. no-no ◽  
Author(s):  
Bryan L. Foster ◽  
Erin J. Questad ◽  
Cathy D. Collins ◽  
Cheryl A. Murphy ◽  
Timothy L. Dickson ◽  
...  
Keyword(s):  
Soil Fertility ◽  
Plant Species ◽  
Species Sorting ◽  
Seed Availability ◽  
Fertility Gradient ◽  
Soil Fertility Gradient
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